Fast Atom Bombardment Mass Spectrometry Research Articles

Biosurfactants—An Overview

AbstractThe large structural and functional variety of bio‐surfactants (BS), which are produced by microorganisms, leads to the use of several methods to study these amphiphilic molecules. This review seeks to consolidate information on various surface‐active product extraction techniques, microbiological screening methodologies, and analytical terminologies utilized in this sector. The potential benefits and drawbacks of various approaches for studying cell biomass or microbial culture broth for the generation of surface‐reactive chemicals are also discussed. Additionally, the most popular techniques for detection, structural characterization, and purification of a variety of BS are introduced. A number of straightforward techniques are described in detail, including dialysis, ion exchange, solvent extraction, ultrafiltration, lyophilization, and thin layer chromatography (TLC). In addition to more sophisticated techniques like nuclear magnetic resonance (NMR), fast atom bombardment mass spectroscopy (FAB‐MS), gas chromatography‐mass spectroscopy (GC‐MS), high‐pressure liquid chromatography (HPLC), and infrared (IR), proteolysis and sequencing of amino acid are also explained. In this field of study, it is quite necessary to combine several analytical techniques, and it often takes multiple iterations to purify, isolate, and characterize different surface‐active substances. The numerous approaches that are essential for researching bio‐surfactants are covered in this review.

Solid state conversion of novel coordinated precursors to visible light active photocatalysts with enhanced photocatalytic activity

The new polydentate N'1,N'3‐bis((E)‐3‐oxopentan‐2‐ylidene)malonohidrazide chelating agent (H2L) and its coordinated complexes of Co2+, Cu2+, and Ni2+ were prepared and characterized by elemental analysis, molar conductance, and spectra (Fourier transform infrared [FT‐IR], ultraviolet–visible spectroscopy [UV–vis], and Fast‐Atom Bombardment Mass Spectrometry (FAB‐MS). Also, thermal and magnetic investigations were conducted. X‐ray single crystal of the H2L ligand revealed a triclinic structure with space group P‐1. In this study, we provide a one‐pot preparation approach for transition metal oxide nanoparticles (NPs) such as CuO, Co3O4, and NiO NPs. The methodology entails the thermal decomposition of coordinated metal precursors in a solid‐state environment, obviating the necessity for agitation and rinsing. The remarkable significance of this method lies in its ability to produce highly pure NPs without the requirement of washing, and it allows for systematic and efficient production. Herein, we propose a large‐scale, environmentally benign and renewable, transition metals oxide NPs such as CuO, Co3O4, and NiO using solid‐state thermal degradation of their coordinated precursors. The NPs are subjected to analysis employing a range of techniques, such as X‐ray powder diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), N2 sorpometry (BET), and UV–vis). The photocatalytic activities of the synthesized NPs were assessed using photodegradation of organic contaminants in wastewater.

Long-Wavelength Absorbing Benzimidazolo-Chlorin for Enhanced Photodynamic Therapy.

In this study, we condensed methyl pyropheophorbide-a (2) with 1,2-phenylenediamine to synthesize benzimidazolo-chlorin (3a) as an effective near-infrared photosensitizer (PS) with an absorption maximum of 730 nm. The ability of 3a to generate singlet oxygen, as well as its photodynamic effect on A549 and HeLa cells, was investigated. PS exhibited strong phototoxicity and negligible dark toxicity. Its structure was examined by UV-visible spectroscopy, nuclear magnetic resonance, and high-resolution fast atom bombardment mass spectrometry.

(1R,2S,5R)-5-Methyl-2-(propan-2-yl)cyclohexyl 4-amino-3-phenylbutanoate hydrochloride: Synthesis and anticonvulsant activity

Abstract Ester based on l-menthol and phenibut ‒ (1R,2S,5R)-5-methyl-2-(propan-2-yl)cyclohexyl 4-amino-3-phenylbutanoate hydrochloride was obtained in 78% yield using N,N′-dicyclohexylcarbodiimide as a coupling reagent along with catalytic amount of 4-dimethylaminopyridine. The obtained product was characterized by FT-IR, fast-atom bombardment-mass spectrometry along with 1H-NMR and 13C-NMR spectral analysis; the purity was assessed using high-performance liquid chromatography. Phenibut ester has been examined on the models of chemically- and electrically-induced seizures for potential anticonvulsant profile.

Alkaline-earth metal(II) complexes of salinomycin – spectral properties and antibacterial activity

Abstract In the present paper the synthesis and structural characterization of alkaline-earth metal(II) complexes of the polyether ionophorous antibiotic salinomycinic acid (SalH.H2O) are discussed. The complexes [M(Sal)2(H2O)2] (M = Mg2+, 1; Ca2+, 2; Sr2+, 3; Ba2+, 4) were obtained reacting salinomycinic acid and Et4NOH with the corresponding metal(II) salts at metal-to-ligand-to-base molar ratio of 1:1:1. The spectral properties of 1–4 were characterized using infrared spectroscopy, fast atom bombardment-mass spectrometry, nuclear magnetic resonance and elemental analysis data. The crystallinity degree and morphology of complex 2 were studied by X-ray powder diffraction and transmission electron microscopy. The biometal(II) salinomycinate complexes 1 and 2 possess an enhanced antimicrobial activity compared to the parent antibiotic against Gram-positive bacteria. The comparison between the effectiveness of the complexes, reported here, and the already known isostructural coordination species of salinomycin and monensin (MonH.H2O), revealed that magnesium(II) and calcium(II) monensinates appear to be promising antibacterial agents against Bacillus subtilis, Bacillus cereus and Micrococcus luteus.

Stereocalpin B, a New Cyclic Depsipeptide from the Antarctic Lichen Ramalina terebrata.

Stereocalpin B, a new cyclic depsipeptide (1), and a new dibenzofuran derivative (3), were isolated from the Antarctic lichen, Ramalina terebrata (Ramalinaceae), along with a known cyclic depsipeptide (2). The structures of new compounds were characterized by comprehensive spectrometric analyses; high-resolution fast atom bombardment mass spectrometry (HR-FABMS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Stereocalpin B (1) existed in a rotameric equilibrium, which was confirmed using nuclear Overhauser effect spectroscopy (NOESY)/exchange spectroscopy (EXSY) spectrum. Absolute configurations of the amino acid units in 1 were assigned using the advanced Marfey’s method and subsequent NOESY analysis of the 5-hydroxy-2,4-dimethyl-3-oxo-decanoic acid residue confirmed the complete stereochemistry of 1. Compounds 1-3 exhibited moderate antimicrobial activities against E. coli, with the IC50 values ranging from 18–30 μg/mL. Compound 2 exhibited cell growth inhibition against HCT116 cell lines, with the IC50 value of 20 ± 1.20 μM, and compounds 1 and 2 also showed potent anti-inflammatory activities against lipopolysaccharide (LPS)-induced RAW264.7 macrophages with the IC50 values ranging from 5–7 μM.

In vitro anticancer and antibacterial potentials of selected medicinal plants and isolation and characterization of a natural compound from Withania coagulans.

In the current study, five different plants, Syzygium Cumini, Fagonia cretica, Acacia modesta, Withania coagulans, and Olea europaea aqueous extracts were prepared and applied against the anticancer and antibacterial activities. It was observed that O.Europaea extract shows the highest anticancer activity with cell viability of 21.5%. All the five plants extract was also used against the inhibition of Bacillus subtilis where O.Europaea extract shows a promising inhibitory activity of 3.2cm followed by W.coagulans. Furthermore, W.coagulans was subjected to the process of column chromatography as a result a withanolide was isolated. The fast atom bombardment mass spectrometry (FAB-MS) and high resolution fast atom bombardment (HRFAB-MS) [M+1] indicated molecular weight at m/z 453 and molecular formula C28H37O5. The UV-Vis. spectrum shows absorbance at 210nm suggesting the presence of conjugated system, and Fourier-transform infrared spectroscopy (FTIR) was recorded to explore the functional groups. Similarly, 1D and 2D NMR spectroscopy techniques such as 1H, 13C NMR, correlation spectroscopy (COSY-45°), heteronuclear single quantum correlation (HSQC), heteronuclear multiple bond correlation (HMBC) and Nuclear Overhauser effect Spectroscopy (NOESY) techniques was carried out to determine the unknown natural product. The collective data of all these techniques established the structure of the unknown compound and recognized as a withanolide.

Research progress of tannins in traditional Chinese medicines in recent ten years

In this paper, the newly isolated tannins were sorted after a review of the literature concerning tannins in recent 10 years, and their research progress was summarized in terms of extraction, isolation, pharmacological activity and metabolism. Hydrolysable tannins and condensed tannins are the main structural types. Modern research shows that tannins have many pharmacological effects, such as bacteriostasis, antioxidation, antitumor, antivirus and blood glucose reduction, and have broad development prospects. They are usually extracted by water, ethanol and acetone and isolated and purified by macroporous resin and gel column chromatography. The packings commonly adopted for the column chromatography mainly included Sephadex LH-20, Diaion HP-20, MCI-gel CHP-20 and Toyopearl HW-40. Modern analytical techniques such as nuclear magnetic resonance spectroscopy(NMR), fast atom bombardment mass spectrometry(FAB-MS) and circular dichroism(CD) are generally used for the structural identification of tannins. Howe-ver, their isolation, purification and structural identification are still challenging. It is necessary to use a variety of high-throughput screening methods to explore their pharmacological activities and to explore the material basis responsible for their functions through experiments in vivo.

Hemilability in neutral RuCl2(η1−P∩O)2(N∩N) complexes: Physicochemical, trans/cis-isomerization, thermal and A DFT/TD-DFT

Hemilabile neutral Ru(II) complexes of type trans-RuCl2(η1P∩O)2N∩N, (P∩O = Ph2PCH2CH-(OCH3)2,N∩N = 1,3-diaminopropane (1) and 1,2-diaminopropane (2) were made available in high yield. The hemilabile phenomena in P∩O ligand formed RuCl2(η2P∩O)2, the trans to cis isomerization and Halochromism reactions were monitored individually via liquid 31P{1H} NMR. The desired new complexes were identified by UV–Vis, CV, CHN-elemental analysis, fast atom bombardment mass spectrometry (FAB-MS), 1H-, 31P-{1H}, 13C{1H}-NMR and TG/DTA. Moreover, complex 1 was subjected to DFT-optimization, HOMO/LUMO, density of state (DOS), and molecular electrostatic potential (MEP) computations. The experimental thermal behavior was also determined by TG/DTA in an open atmosphere. The time-dependent density functional theory (TD-DFT) was matched successfully to the Absorption behavior of complex 1 in CH2Cl2.

Purpurogallin의 감마선 조사에 따라 생성되는 항산화 물질

Gamma irradiation is a promising technique for improving the quality, safety, and shelf-life of foods. However, research on radiation-induced systemic degradation related to changes in the chemical structure and biological activity is still limited. In this study, radiolytic degradation and antioxidant activity enhancement of purpurogallin were studied in response to varying dose of gamma irradiation. Pure purpurogallin in methanol was exposed to gamma rays from 10 to 100 kGy. Purpurogallin reaction mixture was completely degraded when irradiated with 50 kGy and showed an increased antioxidation activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS+). It also exhibited hydroxyl radical scavenging ability. The structure of the newly-formed simple phenolic compound, pyrogallol (2) from gamma irradiated purpurogallin at 50 kGy was characterized using 1H, 13C, heteronuclear singles quantum coherence (HSQC), and heteronuclear multiple bond correlation (HMBC) NMR, and fast atom bombardment mass (FABMS) spectroscopy. Compared to the parent purpurogallin, the small phenolic molecule (2) exhibited significantly enhanced antioxidant activity against DPPH, ABTS+, and hydroxyl radical scavenging activities with SC50 values of 9.5±0.3, 12.6±0.4, and 48.1±0.9 μM, respectively. These results indicate that degradation of purpurogallin induced by gamma irradiation might enhance its antioxidant property.

Successful treatment of infantile oxysterol 7\u03b1-hydroxylase deficiency with oral chenodeoxycholic acid

BackgroundDeficiency of oxysterol 7α-hydroxylase, encoded by CYP7B1, is associated with fatal infantile progressive intrahepatic cholestasis and hereditary spastic paraplegia type 5. Most reported patients with CYP7B1 mutations presenting with liver disease in infancy have died of liver failure. However, it was recently reported that two patients treated with chenodeoxycholic acid survived. Correlations between the phenotype and genotype of CYP7B1 deficiency have not been clearly established.Case presentationA 5-month-7-day-old Chinese baby from non-consanguineous parents was referred for progressive cholestasis and prolonged prothrombin time from one month of age. Genetic testing revealed compound heterozygous mutations c.187C > T(p.R63X)/c.334C > T(p.R112X) in CYP7B1, and fast atom bombardment mass spectrometry analysis of the urinary bile acid confirmed the presence of atypical hepatotoxic 3β-hydroxy-Δ5-bile acids. While awaiting liver transplantation she was orally administered chenodeoxycholic acid. Her liver function rapidly improved, urine atypical bile acids normalized, and she thrived well until the last follow-up at 23 months of age. Her 15-year-old brother, with no history of infantile cholestasis but harboring the same mutations in CYP7B1, had gait abnormality from 13 years of age. Neurological examination revealed hyper-reflexia and spasticity of the lower limbs. Brain MRI revealed enlarged perivascular space in the bilateral basal ganglia and white matter of frontal parietal.ConclusionsIn summary, these findings highlight that the phenotype of CYP7B1 deficiency varies widely, even in siblings and that early administration of chenodeoxycholic acid may improve prognosis.

Guaianolide Sesquiterpene Lactones from Centaurothamnus maximus.

Centaurothamnus maximus (family Asteraceae), is a leafy shrub indigenous to the southwestern Arabian Peninsula. With a paucity of phytochemical data on this species, we set out to chemically characterize the plant. From the aerial parts, two newly identified guaianolides were isolated: 3β-hydroxy-4α(acetoxy)-4β(hydroxymethyl)-8α-(4-hydroxy methacrylate)-1αH,5αH, 6αH-gual-10(14),11(13)-dien-6,12-olide (1) and 15-descarboxy picrolide A (2). Seven previously reported compounds were also isolated: 3β, 4α, 8α-trihydroxy-4-(hydroxymethyl)-lαH, 5αH, 6βH, 7αH-guai-10(14),11(13)-dien-6,12-olide (3), chlorohyssopifolin B (4), cynaropikrin (5), hydroxyjanerin (6), chlorojanerin (7), isorhamnetin (8), and quercetagetin-3,6-dimethyl ether-4’-O-β-d-pyranoglucoside (9). Chemical structures were elucidated using spectroscopic techniques, including High Resolution Fast Atom Bombardment Mass Spectrometry (HR-FAB-MS), 1D NMR; 1H, 13C NMR, Distortionless Enhancement by Polarization Transfer (DEPT), and 2D NMR (1H-1H COSY, HMQC, HMBC) analyses. In addition, a biosynthetic pathway for compounds 1–9 is proposed. The chemotaxonomic significance of the reported sesquiterpenoids and flavonoids considering reports from other Centaurea species is examined.

Lavencidin, a polyene macrolide antibiotic from Streptomyces lavendulae FRI-5.

In our screening program for new biologically active compounds, a new polyene macrolide, lavencidin (1), along with known compound RKGS-A2215A (2), was isolated from the fermentation broth of Streptomyces lavendulae FRI-5 by changing the composition of liquid medium normally used for the strain. Their structures were elucidated by spectral methods (high-resolution fast-atom bombardment mass spectrometry (HRFABMS) and nuclear magnetic resonance (NMR)). Compound 1 includes a conjugated pentaene moiety together with six hydroxy groups and a carboxylic acid as a side chain. Lavencidin (1) showed moderate growth-inhibitory activity against yeast and was cytotoxic against human cancer cell lines with low-micromolar IC50 values.

Structure Elucidation of Betulinic Acid from Sesbania grandiflora Root

Betulinic acid, a known triterpene compound that has been successfully isolated from the ethyl acetate extract of the root of Sesbania grandiflora. The structure elucidation of betulinic acid was performed using one- and two-dimensional nuclear magnetic resonance, ultraviolet and infrared spectroscopy, and fast atomic bombardment mass spectrometry as well as by comparing with the literature data. This compound was found for the first time from the Fabaceae family, in particular Sesbania grandiflora.

Synthesis of Recyclable Magnetic Cellulose Nanofibers from Ionic Liquids for Practical Applications in Separation Science.

The present study focused on coupling cellulose nanofibers (alternative materials for plastics and metals) with a magnetic ionic liquid (synthesized by a microwave-assisted method) through mixing to yield magnetic cellulose nanofibers (MCNFs) that can be recycled by attracting them to a magnet. Accordingly, two types of ionic liquids were synthesized: (a) 1-butyl-3-methylimidazolium tetrachloroferrate(III) {[bmim] FeCl4} and (b) 1-glycidyl-3-methylimidazolium tetrachloroferrate {[glmi]FeCl4}, which were characterized by the fast atom bombardment mass spectrometry (FAB-MS) technique. Impregnation of the cellulose nanofibers with the {[bmim]FeCl4} ionic liquid caused the latter to be physically adsorbed onto the nanofibers to produce {MCNF@{[bmim]FeCl4}, whereas the corresponding {[glmi]FeCl4} ionic liquid was chemically bonded to the cellulose nanofibers to yield magnetic {MCNF@[glmi]FeCl4} nanofibers. Under the experimental conditions used, the corresponding magnetic moments were 0.222 A m2 kg-1 for {MCNF@ {[bmim]FeCl4} and 0.095 A m2 kg-1 for {MCNF@[glmi]FeCl4}.

Synthesis and combustion inhibition efficiency of iron short-chain perfluorocarboxylates

This study reports an experimental exploration of the combustion inhibition efficiency of iron short-chain perfluorocarboxylates, namely, iron trifluoroacetate (FeTFA) and iron pentafluoropropionate (FePFP). The aim is to develop a new phosphor-free fire-extinguishing agent. The synthesized FeTFA and FePFP were characterized by ultraviolet–visible spectroscopy, Fourier-transform infrared spectroscopy, X-ray fluorescence measurements, and fast-atom bombardment mass spectrometry. The FeTFA and FePFP ligands (i) coordinate with the iron ions in bridging form via carboxylate oxygens, (ii) contain no Cl−, and (iii) are hexanuclear complexes with chemical formulas of C18F27O22Fe6 and C27F45O22Fe6, respectively. Suppression trials and thermogravimetric measurements revealed that (i) both FeTFA and FePFP have higher combustion inhibition ability at lower suppressant concentrations than ammonium dihydrogen phosphate (an active component in conventional fire-extinguishing agents), (ii) FePFP is remarkably more inhibition-efficient than FeTFA, and (iii) neither FeTFA nor FePFP hinder cellulose pyrolysis and char combustion in the condensed phase. Thermogravimetry–mass spectrometry measurements confirmed that (i) the main gas-phase decomposition product of FeTFA and FePFP is CF3, and (ii) FePFP is a better CF3 generator than FeTFA. The different inhibition abilities of the two complexes were attributed to their different CF3 generation abilities and eases of decomposing the complex.

CRYSTAL STRUCTURES OF QUINOLINYL PALLADIUM(II) COMPLEXES: [Pd(PPh3)2{κ1-C9H6NB}(Cl)] AND [Pd(PPh3)2Cl]2{μ,κ2-C9H6N}

A reaction of Pd(PPh3)4 (complex 1) and 2-chloroquinoline C9H6NCl in a 1:1 molar ratio produces a mononuclear [Pd(PPh3)2{κ1-C9H6NB}(Cl)] complex (complex 2) and a binuclear [Pd(PPh3)2Cl]2{μ,κ2-C9H6N} complex (complex 3). In complex 3, each of quinoline units is bridged through the carbon atom of quinoline groups to one metal center and the nitrogen atom to another metal, forming a six-membered ring with the boat-like geometry. Complexes 2 and 3 are characterized by the elemental analysis, fast atom bombardment mass spectrometry, 31P NMR spectroscopy, and single crystal X-ray diffraction.

Design, synthesis and pharmacological profile of (−)-verbenone hydrazones

AbstractA series of novel (−)-verbenone hydrazones was designed and synthesized via condensation of terpenoid with hydrazides derived from phenoxyacetic acid. The structure of target compounds was confirmed by 1H-NMR and 13C-NMR analysis, Raman and FT-IR spectroscopy, electrospray ionization method and fast atom bombardment (FAB) mass spectrometry. Thermal properties of (−)-verbenone hydrazones 3a–3e were estimated by differential scanning calorimetry and their purity by HPLC coupled to mass spectrometry. Verbenone hydrazones were revealed to exist as Z/E geometrical isomers about C═N bond and cis/trans amide conformers. Verbenone derivatives were estimated as potential anticonvulsant agents after their oral administration against pentylenetetrazole and maximal electroshock-induced seizures in mice. Analgesic effect of hydrazones was studied by topical application on models of allyl isothiocyanate and capsaicin-induced pain. The present findings indicate that verbenone hydrazones contribute to seizure protection both at short (6 h) and long (24 h) time periods by blocking chemical- and electroshock-induced convulsions. Binding of compounds 3a–3e to TRPA1/TRPV1 ion channels was suggested as a feasible mechanism explaining their significant analgesic activity.

A New Chlorinated Phenolic Compound From the Antarctic Lichen, Pertusaria dactylina

A new chlorinated phenolic compound, methyl-3-chloro-2-hydroxy-4-methoxy-6-pentylbenzoate (1) and 4 known compounds (2-5) were isolated from the Antarctic lichen, Pertusaria dactylina ( Pertusariaceae). The structure of the new compound was determined by means of One-dimensional and two dimensional nuclear magnetic resonance (1D and 2D NMR) and high-resolution fast atom bombardment mass spectrometry (HRFABMS) experiments. The antimicrobial activities of compounds 1 to 5 against Staphylococcus aureus and Candida albicans were evaluated. The results showed that compound 1 exhibited a weak inhibitory effect against C. albicans with an IC50 value of 67 ± 7 μg/mL.

Crystal structures of quinolinyl palladium(II) complexes: [Pd(PPh3)2{κ1-C9H6NB}(Cl)] and [Pd(PPh3)2Cl]2{μ,κ2-C9H6N}

A reaction of Pd(PPh3)4 (complex 1) and 2-chloroquinoline C9H6NCl in a 1:1 molar ratio produces a mononuclear [Pd(PPh3)2{κ1-C9H6NB}(Cl)] complex (complex 2) and a binuclear [Pd(PPh3)2Cl]2{μ,κ2-C9H6N} complex (complex 3). In complex 3, each of quinoline units is bridged through the carbon atom of quinoline groups to one metal center and the nitrogen atom to another metal, forming a six-membered ring with the boat-like geometry. Complexes 2 and 3 are characterized by the elemental analysis, fast atom bombardment mass spectrometry, 31P NMR spectroscopy, and single crystal X-ray diffraction.